Lockable NEMA Enclosures: Applications and Polycase Options

Most of us lock our homes, our offices and our vehicles. It’s a simple common-sense precaution that helps secure the most important things in our lives.

That’s why, for some device designers and engineers, lockable NEMA enclosures are a must-have. A lockable enclosure helps safeguard the sensitive and valuable components of an electronics device and keep them secure.

In today’s article, we’ll look at the many reasons why you might need a lockable NEMA enclosure, as well as several of Polycase’s best lockable NEMA enclosures. Each of these models offers reliable and rugged protection for safeguarding your device, from both security breaches and environmental conditions.

Applications for Lockable NEMA Enclosures

There are many applications that may require lockable NEMA enclosures. Generally, enclosures for sensitive devices that are in areas potentially accessible to unauthorized personnel need a locking mechanism. This requirement is most common for outdoor enclosures, but it can be applicable to indoor enclosures as well, particularly in the case of industrial enclosures that protect key systems. Here are a few of the most common applications that require lockable NEMA enclosures:

• Security Systems: Many security systems need an enclosure to house their control units. It’s important for these enclosures to be lockable to prevent unauthorized access to the security system since they control critical functions such as arming and disarming alarms.
• Hazardous Equipment/Materials: Enclosures that house control devices for dangerous equipment will often need to be lockable, as unauthorized access can create extremely hazardous situations.
• Computer Equipment: Sensitive electronics equipment, such as computer server equipment, is a critical security area today. Unauthorized access can lead to stolen equipment or even data security breaches.

Electrical Infrastructure: Critical electrical infrastructure such as junction boxes, power supplies and circuit breakers must be protected not only from impacts and weather factors but from unauthorized access.

Polycase SA-31 Stainless Steel NEMA Enclosure with keyed quarter turn latch lock

Built-In Lock or Padlock?

Typically, you’ll see one of two options employed for a lockable NEMA enclosure: built-in locks and padlock attachment slots. Consider the pros and cons of each when choosing your enclosure:

• Built-In Lock: A built-in lock builds the lock mechanism, including its cylinder and latch, directly into the door of the enclosure. The latch holds the door in place and prevents it from being opened without the key. These locks are extremely secure and hard to defeat, and they don’t require buying any additional equipment. However, they can be more expensive than padlock mechanisms and they require more effort to repair or replace if the operating mechanism becomes jammed.
• Padlock: Some enclosures feature an area that allows a padlock shackle to be inserted. This prevents the enclosure from being opened until the padlock is removed. This is an easy and cost-effective way to secure your enclosures, although it requires the extra step of buying a padlock. Should the padlock ever fail, it can simply be replaced. Padlocks can sometimes be defeated through the use of bolt cutters (although there are ways to make this more difficult, such as placing metal nuts on the shackle to make it more difficult to cut).

Other Factors for Choosing a Lockable Enclosure Box

When you’re deciding on which model of lockable enclosure to specify, here are a few other important aspects to consider:

• NEMA Rating: Just being NEMA rated isn’t enough — you need to know that your enclosure has the correct NEMA rating. An outdoor-rated NEMA 4 enclosure and an indoor-rated NEMA 12 enclosure, for example, offer significantly different levels of protection. Polycase’s NEMA ratings guide is a key resource for making the right choice, especially if your application requires a watertight or dust-tight enclosure.
• Enclosure Material: A wide variety of metallic and non-metallic enclosure materials are available, from stainless steel to polycarbonate to ABS plastic. Each has its own desirable properties, from heavy duty durability to natural resistance to electromagnetic interference. See our enclosure material selection guide for more information to help you decide which material is the best choice for your application. 
• Mounting Features: Some models are designed as wall mount enclosures, while others can be easily mounted to a freestanding utility pole using a pole mount kit. In addition, it’s important to consider the enclosure’s capacity for any internal mounting hardware such as DIN rails that may be necessary to mount your electrical components. Browse Polycase’s selection of mounting kits to get started.
• Cooling and Ventilation: Many enclosures need cooling and ventilation features to control their internal temperatures and prevent moisture buildup. Learn what kind of enclosure accessories are available for each model and assess whether they suit the needs of your application. See our guide to calculating temperature rise in enclosures, as well as our guide to preventing condensation.

Lockable NEMA Enclosures from Polycase

Polycase’s selection of hinged electrical enclosures includes many different high-performance waterproof locking electrical boxes. Our options include:

• Polycase SA Series: The SA Series are stainless steel NEMA 4X enclosures with a keyed quarter turn lock built into the door (key included). They’re highly resistant to break-ins and tampering, and they offer excellent corrosion resistance thanks to their stainless steel construction. Their weatherproof rubber gasket seals out everything from rain and snow to windblown dust.
• Polycase SB Series: The SB Series is the NEMA 4X-rated carbon steel cousin of the SA Series, and it has many of the same great features, including the keyed quarter turn lock and weatherproof gasket. An excellent option for applications which need the dependable performance and desirable properties of steel at a lower price point than a stainless steel enclosure.
• Polycase ZH Series: The ZH Series polycarbonate plastic enclosures feature a hinged latch design, with a space included on the latch where a padlock can be easily attached. They’re NEMA 6P-rated for the ultimate level of device protection, and their impact-resistant polycarbonate is designed to provide reliable and rugged performance.
• Polycase WQ Series: Designed with a fiberglass reinforced polycarbonate base for added strength, the IP67 rated WQ series is available in over 20 sizes. An optional clear cover provides visibility for those applications where viewing your internal components is vital.

Polycase WH Series: Another popular series of NEMA enclosures, the WH Series feature a built-in padlock slot. Available in both an indoor rated, economical ABS option as well as outdoor rated polycarbonate versions.

Polycase ZH Series with padlock slot

Polycase’s enclosure experts are always happy to help our customers find the lockable NEMA enclosures they need. Call us at 1-800-248-1233 toll free or contact us online.